Brush



n brush; and

ance of the block to shocks.

the cotton libre, which is from `tive to ten Patented @et i9, 392@ nuten tenante narrar Fries@ STUART B. MOLONY, 0F ACONSHOHOGKEN', JPETNSYLVANIA:

nnnsn. v

application led May 1 6,

Theinvention is illustrated-inl the accompany1ng,draw1ng,in which- Fg.' l is a plan View of the brush back;

of Fig. l;

wf F ig. 3 is a plan View of the completed `Filgyi is a'side elevation. p This invention relates to anirnprovement in the construction of the block :tor holding thenbristles shown in cross section in 1, Fig. 2, andfconsists in an improved construction of theblock for the purpose of increasing its Y-s`tre r1f th. l

Ili`his type of brush in which the bristles areifset yin small clusters, or .sets, in small lholes inthe block, is commonly used :for

calcimine or 'watery-paints, and the block must not only be waterproof so it will not swell rand warp, ,but' it must be strong enoughto resist the vswelling action of the water onthe'brist'les -But I do not wish to limit myself to such calciminebrushes as my improvement is suited for use for floor 'I waxin brushes aintersdust brushes etc.

l :P 7 a Where a strong"block is required to-resist mechanical shocks.

y The blocks for calcimine brushes are com-- monly made of hard rubber, but while most of the .brushes made with hard rubber blocks are satisfactory it'cannot be depended upon to stand severe mechanical shocks, especially in cold weather when hard rubber is quite brittle. lin order to overcome this brittle ness ll have added lfibres, such as'cotton iire, to the hard rubber compound, andr have found that ,the `addition of twenty percent oit cotton b're, `by weight, to the pure hard rubber compound consisting of hard rubber and sulphur, greatly increases the resisttimes as strong'as thehard rubber itself,

binds the rubber together and decreases the tendency to cleavage.

lin'order to better take advantageot the strength oit iibre made np blocks of alter.

natelayers .ot canvas and hardrubber by ealendering the hard rubber compound into i d l plies of canvas, stacking s "i at o bloeit' Fig. 2 is a cross-sectional View upon linerl`his is because,

1923. Serial No. 639,236.

ahmed. nk@j a. meer of Wood. r also buia upblocks of alternate layers of hard rubber and copper screening and found that this made an excellent block and could be @o bored.- l Y p When paper is used inalternate layers with hard vrubber it is necessarytov first impregnate the paper with hard rubber com pound. rlhis can best be done by dissolving (554 the compound in a rubber solvent, such as solvent naptha, passing the paper through the solution slowly/ enough to allow it to penetrate4 properly, drying out the'solvent,

and finally stacking the sheets together in suilicient number to form the slabsof the required thickness and vulcanizingunder a press.

The mechanical properties of hard rubber, however, are very sensitive to temperate turel changes, and rubber which is hardenough in Warm water is too brittle at winter temperature to have the proper strength. ll iind that blocks built up of alternate layers of Acanvas or paper bound tono gether with the synthetic resin resulting from lthe condensation of phenol and formaldehyde form a block less senstive to temperature changes than those in which hard rubber is used as in binding material. In et forming these the blocks are made by impregnating the single sheets of canvas with the synthetic resin in syrup form, 'drying the impregnated sheets in a vacuum dryer.

at a temperature too low to cause polyno mel-ization of the resin, stacking' the sheets together under a hydraulic press, preferably. in a vacuum dryerand pressing between heated platens at a suilicient temperature and for a suflicient length of time o5 'to cause thorough polymerization and hardening of the resin.` About 22() degrees F. for

.a period of six hoursl appears suihcient for this.

While these and thel canvas-hard-rubber tuo,

blocks may bedescribed as alternate layers of canvas, onpaper, and binding material, this may not be an exact description as in both cases thebinding material is impregnated into the fabric or fibre and the bindmaterial can not be said to remain in layers.

resin prevents a good union. 1 find, however, that a good union can be made by first platingv the metal sheets Witheopper, neXt dipping them into a solution of hard rubber compound dissolved in 'solvent naptha, evaporating the naptha, and then applying thefsynthetic resin', and `then stacking the metal sheetstogether and vulcanizing and polymerizing the Whole mass with# heat. 'The film ofphard rubberv which will form astrong union with acoppered metal- Where Wire screening is .used instead of plates this is not so necessary as the Wire is imbedded in the resin and cannot brealvf away so easily.

In Fig 1 is shown in plan view the block holding the bristles. It is bored'with a large number of' taper holes, 3, to receive the clumps of bristles, 4, Fig. 2. These are cementedtogether in a solid clump, or set with various setting materials such as shellac, rubber, synthetic resin, etc. They can either be set in the holes While the setting material is plastic and then the setting material can be hardened lin place, or the clumps fcan be previously cemented .together and hardened in the proper sized clump with the proper taper to fit the holes and then introduced into the holes after the cementing material is hard. Il/Vhen this is dene the clumps, if desired, can be cemented in the-holes with a cement different from l. In a brush, a brush "head comprising necessary for hardy Figure 3 is the plan yview of the completed brush showing thecap, 7, Which is fastened down over the tapered holes' after" the bristles are in place to holdthem in, and' the handle, 8, which is held lin .the square hole, 9, Fig. l. y

Fig. llfis. the elevation l'of the completed brush. 'n

In making these blocks itis customary to make upgthe solid block and bore the holes 'after the block has been vhardened to ai solidmass. It is possible, however, to punch the holes in the separate sheets of paper, or fabric, before the sheets are stacked together, and, of course, before the; hardening of thebinding materials. If this Ais done, and the separate ifperforated'A sheets are stacked @over holes and so,V savethe cost of boring.

-l'.claim:,Y

-a mould consisting :of conical metal plugs, 'it is possibl to form the block With moulded a solid laminatedblock which is .made of a plurality of layers of fibrous material im- `pregnated'and bound together by a hardened plastic material, -tuft sockets formed in said block, and bristle tufts mounted in said sockets.

2. In a brush, a brush head comprising a solid laminated block-Which ismade of a plurality of layers of fibrous material impregnated and boundtogether by a hardened synthetic resin, tuft sockets formed in said block extending through a plurality of laminations, and bristle tufts mounted in said sockets. Y

3. In a brush, a brush vhead comprising a solid laminated block which is made of a plurality of layers of Woven material impregnated and bound together'by an aldehydephenolic resin, tuft sockets formed in said block extending through a plurality of laminations, bristle tuftsmounted Iin said sockets, and a handle fitted into said block.

4. In a brush, a brush headcomprising a solid laminated block which is made of a pluralityof layers of Woven fabric impregnated and bound together by a' hardened plastic material, tuft sockets formed in said block, and bristle tufts mounted in said Sockets.

STUART MOLONY.

a hole in 

